The present invention relates, generally, to a system and method for treating and removing tissue and, more particularly, to a system and method of use which includes a cryosurgical instrument for isolating and freezing unwanted living tissue and means for vibrating or otherwise treating the cryogenically-treated tissue and removing the tissue.
In many types of medical procedures, tissue specimens of a patient are removed either for diagnostic purposes to study the tissue or for treatment purposes. For example and quite frequently, these tissue specimens include a cancerous tumor or other unwanted localized growth which is then preferably entirely excised from the patient during the medical procedure.
It is important that the cancerous tumor or other growth is localized and entirely removed from the patient to reduce or eliminate the risk that the tumor will return over time and/or will spread to other parts of the body. Therefore, in order to ensure that the tissue associated with the tumor is completely removed, the exterior of the removed section is carefully microscopically studied in order to determine whether there is only good healthy tissue or whether unwanted tissue is present. A physician can thus determine if a portion of the tumor has been left within the good healthy tissue. If this occurs, the physician removes another deeper layer of the good tissue and again performs the procedure.
However, one of the associated risks of removing cancerous tumors is that during one or more of the medical procedures, a portion of the cancerous tumor may separate and spread to another part of the patient""s body. This may result in further medical complications including the risk that the cancer may spread to another part of the patient""s body. It is therefore important that great care and precision be taken in removing the cancerous tissue (tumor).
Typically, the surgical approach for removing the cancerous tissue has involved open surgical procedures. However, such procedures may be accompanied by surgical trauma, such as formation of scar tissue, lengthy recuperation and pain and therefore there has been an increasing desire to expand the use of microsurgical techniques. These microsurgical techniques require the use of highly specialized instruments and therefore are generally much more intricate, time-consuming, and stressful than open surgical procedures. However, the use of microsurgical techniques does greatly reduce some of the common surgical traumas associated with open surgical procedures.
Over the past years, cryosurgical procedures have been advanced and more applications are being discussed for such surgical procedures. Cryosurgery is a surgical procedure that uses freezing temperatures to destroy tissue. Until recently, cryosurgery was utilized almost entirely for the treatment of tumors on the outer surface of the body, such as for treatment of skin cancer. Generally, in cryosurgical procedures, the tumor or the like is frozen to a temperature of preferably about xe2x88x9250xc2x0 C. in order to attempt to completely destroy all of the cells of the tumor. After treating the cells of the tumor, the tumor is typically left in the body for the body to absorb. Thus, the tumor is not removed but rather remains in the body as the extent of the cryosurgical procedure is to simply freeze the cells to a point which hopefully causes the destruction of the cells.
One of the associated disadvantages is that it is difficult, if not impossible, to observe the extent of the frozen region using more conventional cryosurgical instruments. Thus, the difficulty with performing a cryosurgical procedure is that it is not easy to determine whether all of the cells, associated with the nondesirable tissue, have been destroyed. This is especially true when the surgeon simply tries to cryogenically treat only the nondesirable tissue itself. Cryosurgery is therefore a rather imprecise procedure and it is difficult to control the actual cryogenic freezing and destroying of all of the cells associated with the nondesirable tissue. For example, it is difficult to control the freezing gradient and rate of freezing when using cryosurgical instruments. It is also very difficult to predict or determine how many cells of the nondesirable tissue are destroyed during the cryosurgical procedure. As one of skill in the art will appreciate, it is of great importance that all of the cells associated with the nondesirable tissue are destroyed because the existence of even a few of these cells can cause regrowth of the nondesirable tissue and also provides an opportunity for the cells to travel to other locations of the body. Because the treated tissue is left in the body for absorption, any cells which are not destroyed remain in the body and can spread to other locations.
Advances in monitoring and imaging techniques have expanded the potential applications for cryosurgical procedures and have permitted this type of procedure to treat tissue deep within the body, e.g., organ or gland tissue. Monitoring by imaging techniques, such as magnetic resonance imaging or ultrasound, can be used to intraoperatively determine, in real time, the extent of the tumors as well as that of the frozen tissue during cryosurgery. Ultrasound techniques work by sensing a pressure wave from a pressure transducer. The wave is reflected from boundaries between regions that have differences in acoustic impedance such as between tumors and normal tissue, blood vessels and tissue and frozen and unfrozen tissue. The reflected wave is identified by the pressure transducer and the extent of the tumor, or of the frozen region, is shown on a monitor. Following computerized interpretation of the data, this procedure facilitates an accurate identification of the extent of the tumor and of the frozen region during the cryosurgery.
In addition, there is now a better understanding of the process by which a cell freezes and is destroyed. It is believed that freezing in tissue is greatly influenced by the structure of the tissue. The destruction of the frozen tissue is promoted by the fact that during freezing the vasculature network of the tissue is destroyed and, therefore, cancerous and other nondesirable cells in the region that has been frozen are deprived of their blood supply after thawing and die because of ischemic necrosis. The destruction of frozen tissue also results because ice spicules that are formed during the freezing process rupture the cell membranes and therefore cause the destruction of these cells.
It is therefore desirable to provide a surgical system and method for treating and removing cancerous or other nondesirable tissue from deep within a patient""s body, e.g., within an organ or gland, wherein the system is simple yet effective and eliminates or substantially reduces the risk that cancerous cells might spread to other locations and also overcomes the disadvantages associated with the more conventional procedures.
The present invention provides a surgical system and method of use for treating and removing unwanted tissue, such as a cancerous tumor or other growth, which is formed within a patient""s body, e.g., within an organ, gland, or other internal part of the body. The present system is simple yet effective to use and provides a relatively minimally-invasive surgical approach to treating and removing such unwanted tissue.
In one embodiment, a single probe type instrument is used to carry out the surgical procedure of the present invention. The instrument includes a delivery system for delivering a cryogenic fluid to a tip portion of the instrument so that the unwanted tissue is frozen by being placed in contact with the cryogenically-cooled tip portion. The instrument also includes means for vibrating the tip portion to cause the disintegration and break-up of the cryogenically-treated tissue. Preferably, the tip portion is vibrated at frequencies to cause the frozen tissue to disintegrate and break apart. The disintegrated, frozen broken-up pieces or frozen granules of tissue are preferably suspended in a super cooled irrigation fluid which is introduced to the operative site using the instrument. A suction component of the instrument then aspirates the super cooled irrigation fluid and broken-up pieces of the frozen tissue from the operative site. It will be appreciated that other types of devices may be used to disintegrate and break apart the tissue. For example, an impacting device with a rotatable tip may be incorporated into the single probe type instrument instead of a vibrating tip.
More specifically and in accordance with one aspect of the present invention, an ice mass, e.g., an ice sphere, forms during the cryosurgery and completely encompasses the unwanted tissue so that all of the unwanted tissue is maintained at a temperature below freezing. The ice mass forms because individual cells are formed largely of water and thus exposure to temperatures below their freezing point causes the cells to freeze and expand. When a number of surrounding tissue cells freeze and expand, they collectively form the ice mass. The formation of the ice mass serves to isolate the unwanted tissue by encompassing it within the ice mass and importantly makes sure that all of the cells of the unwanted tissue are continuously maintained in a frozen state. By preferably encompassing the unwanted tissue within the ice mass, the frozen unwanted tissue may easily be removed. In other words and according to the present invention, the unwanted tissue is removed while in a frozen state. The complete removal of the unwanted tissue, while it remains in a frozen state, eliminates the risk that any cells of the unwanted tissue remain within the body.
In another embodiment, two or more surgical instruments are used. A system according to this embodiment generally includes a cryosurgical instrument, including a cryoprobe, for cryogenically-treating the unwanted tissue. Within the cryoprobe, a liquid refrigerant (e.g., nitrogen oxide) is circulated so that a probe tip reaches and maintains a temperature below the freezing point of tissue and preferably below about xe2x88x9250xc2x0 C. An incision is made in the skin layer and the probe tip is inserted therethrough so that the probe tip is brought into contact with the unwanted tissue. This contact at these low temperatures causes necrosis to occur in the cells of the unwanted tissue and this results in the freezing of these cells. In addition, ice spicules form during the freezing process and these ice spicules rupture surrounding cell membranes, thereby resulting in the formation of the ice mass.
The cryosurgical instrument thus serves to freeze and isolate the unwanted tissue by encompassing it within the ice mass prior to the tissue being further prepared and then removed according to techniques of the present invention. Suitable monitoring devices, which permit imaging of the operative site, may be used so that the surgeon can determine, in real time, the extent of the unwanted tissue as well as the extent of the frozen tissue. Preferably, the location of the unwanted tissue is first determined using a catscan device, fluoroscope, etc.
After the unwanted tissue has been cryogenically frozen, the tissue is then further prepared and finally removed using one or more surgical instruments. In one embodiment, a vibrating instrument (e.g., sonic or ultrasonic instrument) is used to disintegrate and break apart the frozen tissue to facilitate the removal thereof. In other words, the instrument disintegrates and loosens the frozen tissue which forms the ice mass while still in the frozen state. A tip portion of the instrument is brought into contact with the ice mass and the tip portion is manipulated so that the ice mass surfaces are contacted by the tip portion. The instrument is kept in the vicinity of the formed ice mass so that the ice mass is prevented from thawing by having the instrument continuously cool the tissue or is selectively actuated to intermittently cool the tissue so long as the unwanted tissue remains in a frozen state at all times during the procedure.
In one embodiment, the same surgical instrument which is used to disintegrate and break-up the tissue is also used to remove the frozen tissue from the operative site using techniques such as applying a super cooled fluid treatment (irrigation fluid) to the site and then suctioning the fluid and broken-up frozen tissue away from the site. The fluid treatment causes the tissue to be suspended in the fluid and then the fluid and tissue are suctioned away from the site. The instrument may alternatively comprise any number of suitable impacting devices having a rotatable tip or other moving tip for impacting the tissue to cause the tissue to disintegrate and break-up.
In yet another embodiment, multiple surgical instruments are used to disintegrate and remove the tissue. In one embodiment, a cryoprobe is used to cryogenically freeze the unwanted tissue and form the ice mass which encompasses the unwanted tissue and then a second instrument (e.g., a discectomy needle) is applied to the operative site to cut and remove the unwanted frozen tissue from the patient""s body. The second instrument typically includes some type of suction means for removal of the unwanted cut tissue. As the tissue is removed, continuous application of the cryoprobe to the operative site ensures that the remaining tissue remains frozen and also permits advancement of the ice mass because more tissue is within the cooling radius of the cryoprobe. This further ensure that all of the unwanted tissue is frozen at all times during the removal procedure.
Advantageously, the present invention finds particular utility in the removal of cancerous tumors and unwanted growths from an organ, gland, or other internal part of the patient""s body. Because the unwanted tissue is first cryogenically-treated to form the ice mass encompassing the unwanted tissue, all of the living cells of the cancerous tumor or unwanted growth are frozen and isolated within the ice mass. The ice mass is then preferably maintained in conditions which permit it to remain, frozen (e.g., cryoprobe remains at the operative site) and then completely removed from the patient""s body. This eliminates the risk that living cancerous tissue may be disturbed during the isolation and removal process and then spread to another location of the body causing contamination of this other site.
These and other features and advantages of the present invention will be readily apparent from the following detailed description of the invention taken in conjunction with the accompanying drawings, wherein like reference characters represent like elements.